Generally, a voice-oriented service in the conventional second Generation (2G) Code Division Multiple Access (CDMA) communication system is provided through relatively low speed traffic channels in both a forward direction and a reverse direction. Here, the forward direction denotes a direction from a Node-B to a user equipment (UE), and the reverse direction denotes a direction from a UE to a Node-B. However, users currently desire various services rather than just a simple voice-oriented service. To meet such users' demand, systems that can provide both the voice service and a data service are being developed. In addition, a global standard is being prepared. Recently, a communication system has evolved from a system that provides a voice-oriented service to a 3G system that aims to provide a high speed data service. Many research efforts on a system that realizes a data service-oriented multimedia service are in progress.
In the general communication system, signaling transmission/reception is performed through a direct link between a fixed node-B and User Equipment (UE). A current communication system has low flexibility in realization of a radio network because the position of a Node-B is fixed, and a shadowing region exists, and has difficulty in providing efficient communication service under a wireless environment where a channel state changes much. To overcome the above disadvantages, an alternative of applying a relay method to an existing communication system is being studied.
The relay method allows signaling transmission/reception to be performed through a relay link between a Node-B and UE by installing a relay station between the Node-B and the UE. The relay method can increase the capacity of a system and extend a cell service area. That is, when a channel state is poor between a Node-B and UE, it is possible to provide a radio channel whose channel state is better to the UE, provide a data channel of a higher speed, and extend a cell service area through the relay link.
The relay method is divided into an Amplify-and-Forward (AF) and a Decode-and-Forward (DF). In the AF, a relay station amplifies a reception signal and transfers the same. In the DF, a relay station decodes a reception signal, encodes the signal again, and transfers the same. When using the DF, a relay station may be realized to read a reception signal and transfer a reconfigured signal, and when needed, to directly perform scheduling to allocate a resource.
A multiple relay station may be used for the DF-based CDMA communication system. When the multiple relay station is used, there is a need for a signaling method for effectively adding and deleting a relay link in order to provide the relay link between a Node-B and UE.